Touch screens are gaining in popularity. Many different types of computers are now shipping with touch screens, for example tablets, laptops and convertibles. A convertible is a tablet and a keyboard that can be joined together and used as a laptop, or pulled apart and used as a tablet. Touch screens allow a user to interact with the computer by dragging one or more of their fingers across the screen to complete an action. This allows a much more intuitive user interface (UI). For example a user can zoom in on an object by spreading two fingers apart over the object. Users typically interact with an outer layer of glass on most touch screens. The glass is generally mounted flush with the computer case which allows for the maximum touch screen area.